Smart card for recognizing fingerprint

Abstract

A smart card includes a card body, a transmission unit, a fingerprint sensor, a processing unit and a cover layer. The card body is formed with a cavity. The transmission unit is disposed on the card body, and outputs electricity. The fingerprint sensor is connected to the transmission unit, is accommodated in the cavity, and generates a detection signal after receiving the electricity. The processing unit is disposed in the card body, is connected to the transmission unit and the fingerprint sensor, and performs signal processing on the detection signal after receiving the electricity. The cover layer is disposed in the cavity and covers the fingerprint sensor.

What is claimed is: 
     
         1 . A smart card for recognizing a fingerprint of a user, said smart card comprising:
 a card body having a front surface and a back surface that are opposite to each other, and being formed with a cavity in said front surface;   a transmission unit disposed on said card body, and configured to be coupled to a card reading module, and to output electricity based on an electrical signal generated by the card reading module;   a fingerprint sensor electrically connected to said transmission unit for receiving the electricity therefrom, having a sensing surface for detecting the fingerprint, and being accommodated in said cavity of said card body with said sensing surface opposite to and facing away from said back surface of said card body and receding with respect to said front surface, fingerprint sensor being configured to be activated in response to receipt of the electricity from said transmission unit, and after being activated, to generate a detection signal based on the fingerprint upon detecting the fingerprint;   a processing unit disposed in said card body, electrically connected to said transmission unit and said fingerprint sensor respectively for receiving the electricity and the detection signal therefrom, and configured to be activated in response to receipt of the electricity from said transmission unit and after being activated, to perform signal processing on the detection signal upon receiving the detection signal; and   a cover layer disposed in said cavity of said card body and covering said sensing surface of said fingerprint sensor.   
     
     
         2 . The smart card as claimed in  claim 1 , wherein said cover layer has a dielectric constant ranging from one to eight. 
     
     
         3 . The smart card as claimed in  claim 2 , wherein said cover layer is made of colloid. 
     
     
         4 . The smart card as claimed in  claim 1 , wherein said cover layer has an upper surface that is coplanar with said front surface of said card body. 
     
     
         5 . The smart card as claimed in  claim 4 , wherein said cover layer further has a bottom surface that is opposite to said upper surface, and a thickness of said cover layer between said upper surface and said bottom surface ranges from 25 micrometers to 80 micrometers. 
     
     
         6 . The smart card as claimed in  claim 4 , further comprising a protective layer that is coated over said front surface or said card body and said cover layer. 
     
     
         7 . The smart card as claimed in  claim 1 , wherein said fingerprint sensor in ludes a contact pad, and a controller that is implemented by an unpackaged chip. 
     
     
         8 . The smart card as claimed in  claim 1 , the card reading module including a contactless card reader, wherein said transmission unit includes:
 an induction coil that is embedded in said card body, and that is configured to be inductively coupled to the contactless card reader so as to induce generation of the electrical signal by the contactless card reader to thereby produce a voltage through electromagnetic induction; and   a rectifier circuit that is electrically connected between said induction coil and said fingerprint sensor, and that is configured to generate the electricity based on the voltage produced by said induction coil.   
     
     
         9 . The smart card as claimed in  claim 1 , the card reading module including a contact card reader, wherein said transmission unit includes:
 a converter circuit that is electrically connected to said fingerprint sensor, that is disposed on and exposed from said front surface of said card body, and that is configured to be physically and electrically connected to the contact card reader for receiving the electrical signal from the contact card reader and to convert the electrical signal into the electricity.